Disposable and shielded seed magazine and spacer magazine assembly

ABSTRACT

A magazine assembly for use in a medical instrument, for example, a radioactive seed applicator, includes a housing, a cartridge, a seed plunger and a spring element. The housing is formed of a material adapted to shield transmission of radioactive energy.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/351,034, filed on Jan. 24, 2003, which claims the benefit ofU.S. Provisional Application Ser. No. 60/351,601, filed on Jan. 25,2002, and claims the benefit of U.S. Provisional Application Ser. No.60/351,601, filed on Jan. 25, 2002, each of which is expresslyincorporated herein in its entirety by reference thereto.

FIELD OF THE INVENTION

The present invention relates to a disposable and shielded seed magazinefor use in a medical instrument. The present invention also relates to aspacer magazine assembly for use in a medical instrument.

BACKGROUND INFORMATION

Medical instruments, particularly, seed applicators, are used to implantradioactive seeds into a patient's body. Such seed applicators aredescribed, for example, in U.S. Pat. No. 5,860,909, which is expresslyincorporated herein in its entirety by reference thereto.

Since the seeds are radioactive, it is an object of the presentinvention to provide a disposable cartridge or magazine for a seedapplicator that is shielded to limit transmission of radioactive energy.

The seed applicator described in U.S. Pat. No. 5,860,909 is designed toimplant seeds at spaced locations in a patient's body. The spacing ofthe seeds by the seed applicator is provided by selection and engagementof indentations on a barrel of the applicator with a ball plunger. It isalso possible to provide the desired spacing between subsequent seeds bydelivering and implanting absorbable spacers between seeds. It is anobject of the present invention to provide a spacer magazine assemblyconfigured and adapted for use in conjunction with such spacer and seedarrangement.

SUMMARY

The above and other beneficial objects of the present invention areachieved by providing a disposable and shielded seed cartridge ormagazine as described herein and by providing a spacer magazine assemblyas described herein.

According to one example embodiment of the present invention, the seedmagazine includes a housing formed of a material adapted to limittransmission of radioactive energy from the radioactive seeds containedtherein. Such shielding may be beneficial for shipping purposes, forpreparation purposes and for equipment and personnel safety purposes.

According to an example embodiment of the present invention, the seedmagazine includes a cartridge portion configured to receive at least oneradioactive seed and a housing portion formed of a material having aradiation shield effectiveness substantially equal to that of lead forat least one of I-125, TI-201, Xe-133, Tc-99m and Pd-103. The cartridgeportion may be configured to receive a plurality of seeds. The materialof the housing portion may include a thermoplastic material and may belead-free. The material may be injection moldable and may includeapproximately 94% filler material by weight. The material may have atleast one of a density of approximately 6.90 gms/cc, a flexural yield ofapproximately 11,946 psi, a flexural modulus of approximately 1,210,000psi, a tensile modulus of approximately 1,542,000 psi, an ultimatetensile strength of approximately 6,946 psi, an ultimate elongation ofapproximately 0.795%, a notched izod impact strength of approximately1.202 ft-lb/in, a linear mold shrinkage of approximately 0.005 to 0.006in/in and a material density of approximately 62.5% compared to lead.The material may be autoclaveable.

The material may include a brass material and/or a brass alloy, e.g.,C36000.

The seed magazine may include a seed plunger configured to eject theseed from the cartridge portion, and the seed magazine may be configuredto be non-refillable after ejection of the at least one seed.

The housing may be configured to connect to a seed applicator device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view, partially in cross-section, of an exampleembodiment of a disposable and shielded seed magazine assembly accordingto the present invention.

FIG. 2 is a side elevational view of the magazine assembly illustratedin FIG. 1.

FIG. 3 is a perspective view of a plurality of magazine assembliesarranged in a sterilizing block.

FIG. 4 is a front view of a spacer magazine assembly according to thepresent invention.

FIG. 5 is an end view of the spacer magazine assembly illustrated inFIG. 4.

FIG. 6 is a front cross-sectional view of a head portion of the spacermagazine assembly illustrated in FIGS. 4 and 5.

FIG. 7 is a front view of a cartridge portion of the spacer magazineassembly illustrated in FIGS. 4 and 5.

FIG. 8 is a side view of the cartridge portion illustrated in FIG. 7.

FIG. 9 is an end view of the cartridge portion illustrated in FIGS. 7and 8.

FIG. 10 is a front view of a plunger portion of the spacer magazineassembly illustrated in FIGS. 4 and 5.

FIG. 11 is an end view of the plunger portion illustrated in FIG. 10.

DETAILED DESCRIPTION

FIG. 1 is a top plan view, partially in cross-section, of an exampleembodiment of a disposable and shielded seed magazine assembly 10according to the present invention, and FIG. 2 is a side elevationalview of the magazine assembly 10 illustrated in FIG. 1. As illustratedin FIG. 1, the magazine assembly 10 includes a housing 12, a cartridge14, a seed plunger 16 and a spring element 18. The magazine assembly 10may be configured for use in conjunction with a medical instrument orseed applicator device, such as that described in U.S. Pat. No.5,860,909, which is expressly incorporated herein in its entirety byreference thereto. The magazine assembly 10 is adapted to receive, forexample, fifteen seeds. The magazine assembly 10 may be disposable afteruse.

As illustrated in FIGS. 1 and 2, the housing 12 has a hexagonalcross-section. It should be appreciated, however, that the housing 12may have any desired cross-sectional configuration, including, forexample, a circular cross-section.

The housing 12 may be formed of an autoclaveable, non-toxic,high-density thermoplastic composite material. The material may belead-free, may be injection moldable, may provide a greater yieldstrength compared to lead and may include approximately 94% fillermaterial by weight. An example material for the housing 12 may have adensity, per ASTM Test Method D-792, of approximately 6.90 gms/cc, aflexural yield, per ASTM Test Method D-790, of approximately 11,946 psi,a flexural modulus, per ASTM Test Method D-790, of approximately1,210,000 psi, a tensile modulus, per ASTM Test Method D-638, ofapproximately 1,542,000 psi, an ultimate tensile strength, per ASTMTesting Method D-638, of approximately 6,946 psi, an ultimateelongation, per ASTM Testing Method D-638, of approximately 0.795%, anotched izod impact strength, per ASTM Testing Method D-256, ofapproximately 1.202 ft-lb/in and a linear mold shrinkage, per ASTMTesting Method D-955, of approximately 0.005 to 0.006 in/in, or anycombination thereof. An example material for the housing 12 may have amaterial density of approximately 62.5% compared to lead. Furthermore,an example material for the housing 12 may providing approximately 100%shield effectiveness relative to lead for I-125 (major radiation energyat 35.5 keV gamma), TI-201 (major radiation energy at 71 keV gamma),Xe-133 (major radiation energy at 81 keV gamma) and Tc-99m (majorradiation energy at 152 keV gamma), Pd-103, or any combination thereof.It should be understood that the magazine assembly 10 may be shielded orpartially shielded. The housing 12 may alternatively be formed of abrass material, e.g., C36000 alloy.

FIG. 3 is a perspective view of a plurality of magazine assembliesaccording to the present invention arranged in a sterilizing block 100.Measurements of several example embodiments of a magazine assemblyaccording to the present invention at various locations 120, 140, 160,180 around the sterilizing block 100. The measurements were taken at 10cm from the surface of the sterilizing block 100 with each magazineassembly threaded into to the sterilizing block. The measurements weretaken with an Eberline detector HP-270, model E120.

A first example embodiment of a magazine assembly according to thepresent invention, which is configured as a partially shieldeddisposable cartridge. The housing 12 of the first example embodiment wasformed of the thermoplastic material described above. The first exampleembodiment included a total of 150 seeds (fifteen seeds per cartridge,ten cartridges total) with isotope I-125, having an activity/seed of0.729 mCi and a total activity of 109.350 mCi. A background reading ofapproximately 0.02 mR/h was obtained. At the handle location 120, areading of 23 mR/h was obtained; at the location 140, a reading of 0.03mR/h was obtained; at the location 160, a reading of 0.03 mR/h wasobtained; and at the location 180, a reading of 0.60 mR/h was obtained.

A second example embodiment of a magazine assembly according to thepresent invention, which is configured as a reusable cartridge formed ofstainless steel. The second example embodiment included a total of 100seeds (ten seeds per cartridge, ten cartridges total) with isotopeI-125, having an activity/seed of 0.729 mCi and a total activity of 72.9mCi. A background reading of approximately 0.02 mR/h was obtained. Atthe handle location 120, a reading of 0.02 mR/h was obtained; at thelocation 140, a reading of 0.02 mR/h was obtained; at the location 160,a reading of 0.02 mR/h was obtained; and at the location 180, a readingof 0.02 mR/h was obtained.

A third example embodiment of a magazine assembly according to thepresent invention, which is configured as a shielded disposablecartridge. The housing 12 of the third example embodiment was formed ofthe thermoplastic material described above. The third example embodimentincluded a total of 150 seeds (fifteen seeds per cartridge, tencartridges total) with isotope I-125, having an activity/seed of 0.729mCi and a total activity of 109.350 mCi. A background reading ofapproximately 0.02 mR/h was obtained. At the handle location 120, areading of 0.04 mR/h was obtained; at the location 140, a reading of0.02 mR/h was obtained; at the location 160, a reading of 0.02 mR/h wasobtained; and at the location 180, a reading of 0.50 mR/h was obtained.

A fourth example embodiment of a magazine assembly according to thepresent invention, which is configured as a shielded disposablecartridge. The housing 12 of the fourth example embodiment was formed ofthe brass material described above. The fourth example embodimentincluded a total of 150 seeds (fifteen seeds per cartridge, tencartridges total) with isotope I-125, having an activity/seed of 0.354mCi and a total activity of 53.1 mCi. A background reading was set tozero mR/h. At the handle location 120, a reading of 0.02 mR/h wasobtained; at the location 140, a reading of 0.02 mR/h was obtained; atthe location 160, a reading of 0.02 mR/h was obtained; and at thelocation 180, a reading of 0.04 mR/h was obtained. At a top location200, a reading of 0.04 mR/h was obtained.

FIG. 4 is a front view of an example embodiment of a spacer magazineassembly 210 according to the present invention. The spacer magazineassembly 210 includes a head portion 212, a cartridge portion 214, aplunger portion 216 and a spring member 218. The spring member 218 isarranged to bias the plunger portion 216 in the downward direction asillustrated in FIG. 4. As illustrated in FIG. 5, which is an end view ofthe spacer magazine assembly 210, an E-ring 220 maintains the plungerportion 216 in engagement withe the head portion 212 and cartridgeportion 214. It should be understood that the cartridge portion 214 isadapted by size and configuration to receive a number, e.g., apredetermined number and combination, e.g., alternatingly, of seedsand/or spacers, which are biased by the plunger portion 216 in thedownward direction as illustrated in FIG. 4 toward the distal end of thecartridge portion 214. As further described below, the cartridge portion214 includes a bore 226 for delivery of the seeds and/or spacerstherethrough to be delivered to the treatment site. The spacers may beformed of an absorbable material, e.g., an absorbable polymer.

FIG. 6 is a front cross-sectional view of the head portion 212 of thespacer magazine assembly 210. As illustrated in FIG. 6, the head portionincludes a bore 222 arranged to receive the plunger portion 216 and abore 224 through which an end of the plunger portion 216 extends. Thehead portion 212 may include a threaded, e.g., internally-threaded, end228 engageable with a complementary threaded, e.g., externally-threaded,end of the cartridge portion 214. It should be understood that thecartridge portion 214 and the head portion 212 may be engageable inaccordance with any mechanism and arrangement and that the treaded endsdescribed herein are merely exemplary.

FIG. 7 is a front view of the cartridge portion 214 of the spacermagazine assembly 210, FIG. 8 is a side view of the cartridge portion214, and FIG. 9 is an end view of the cartridge portion 214. Thecartridge portion 214 includes a threaded, e.g., externally-threaded,end 230 engageable with the threaded, e.g., internally-threaded, end 228of the head portion 212. The cartridge portion 214 also includes a bore232 arranged to receive the plunger portion 216 and a magazine of seedsand/or spacers. The arrangement of the bore 232 is complementary to thearrangement of the plunger portion 216, which is more fully describedbelow and includes a circular bore portion and a slotted portion. A bore226 is arranged in the cartridge portion 214 and is adapted to deliverthe seeds and/or spacers therethrough for delivery to the treatmentsite. One or both ends of the bore 226 may be countersunk to facilitatedelivery of the seeds and/or spacers and to prevent interference and/orbinding with the delivery needle.

FIG. 10 is a front view of the plunger portion 216, and FIG. 11 is anend view of the plunger portion 216. The plunger portion 216 includes ashaft 238, a shoulder adapted to abut one end of the spring member 218,an enlarged end portion 234 and a groove 240 adapted to receive theE-ring 220. The enlarged end portion 234 is arranged to bore 232 of thecartridge portion 214, and the end having the groove 240 is adapted tobe inserted through the bore 224 of the head portion 212. The enlargedend portion 234 is adapted by size and configuration to urge the seedsand/or spacers arranged in the cartridge portion 214 by the bias of thespring member 218 toward the bore 226 in the cartridge portion. As eachseed and/or spacer is ejected from the cartridge portion 214, theplunger advances a subsequent seed and/or spacer toward the bore 226 tobe subsequently ejected and delivered to the treatment site.

1. A seed magazine, comprising: a cartridge portion configured toreceive at least one radioactive seed; and a housing portion formed of amaterial, the material having a radiation shield effectivenesssubstantially equal to that of lead for at least one of I-125, TI-201,Xe-133, Tc-99m and Pd-103.
 2. The seed magazine according to claim 1,wherein the cartridge portion is configured to receive a plurality ofseeds.
 3. The seed magazine according to claim 1, wherein the materialincludes a thermoplastic material.
 4. The seed magazine according toclaim 1, wherein the material is lead-free.
 5. The seed magazineaccording to claim 1, further comprising a seed plunger configured toeject the seed from the cartridge portion.
 6. The seed magazineaccording to claim 1, wherein the cartridge portion is configured to benon-refillable after ejection of the at least one seed.
 7. The seedmagazine according to claim 1, wherein the material is injectionmoldable.
 8. The seed magazine according to claim 1, wherein the housingportion is configured to connect to a seed applicator device.
 9. Theseed magazine according to claim 1, wherein the material isautoclaveable.